Radiation-Induced Changes Associated with Obliteration of Brain AVMs after Repeat Radiosurgery.

BACKGROUND AND PURPOSE: Radiation-induced changes can occur after stereotactic radiosurgery for brain AVMs, potentially causing symptomatic complications. We evaluated the incidence of such changes and the efficacy of repeat gamma knife radiosurgery for incompletely obliterated AVMs. MATERIALS AND METHODS: We retrospectively evaluated 150 patients who underwent gamma knife radiosurgery for AVMs between 2002 and 2020; twenty-five underwent further radiosurgical procedures for incompletely obliterated AVMs. We recorded the median margin doses at the first (median, 20 Gy; range, 12-23 Gy; AVM volume, 0.026-31.3 mL) and subsequent procedures (median, 18 Gy; range, 12-23 Gy; AVM volume, 0.048-9.2 mL). RESULTS: After the first treatment, radiologic radiation-induced changes developed in 48 (32%) patients, eight of whom had symptomatic changes. After repeat gamma knife radiosurgery, 16 of 25 patients achieved complete AVM obliteration (64%). The development of radiation-induced changes after the first treatment was significantly associated with successful obliteration by subsequent radiosurgery (OR = 24.0, 95% CI 1.20-483, P = .007). Radiation-induced changes occurred in only 5 (20%) patients who underwent a second gamma knife radiosurgery, one of whom experienced transient neurologic deficits. Between the first and repeat gamma knife radiosurgery procedures, there was no significant difference in radiologic and symptomatic radiation-induced changes (P = .35 and P = 1.0, respectively). CONCLUSIONS: Radiation-induced changes after the first gamma knife radiosurgery were associated with AVM obliteration after a repeat procedure. The risk of symptomatic radiation-induced changes did not increase with retreatment. When the first procedure fails to achieve complete AVM obliteration, a favorable outcome can be achieved by a repeat gamma knife radiosurgery, even if radiation-induced changes occur after the first treatment.

Expression of the G72/G30 gene in transgenic mice induces behavioral changes.

The G72/G30 gene complex is a candidate gene for schizophrenia and bipolar disorder. However, G72 and G30 mRNAs are expressed at very low levels in human brain, with only rare splicing forms observed. We report here G72/G30 expression profiles and behavioral changes in a G72/G30 transgenic mouse model. A human BAC clone containing the G72/G30 genomic region was used to establish the transgenic mouse model, on which gene expression studies, western blot and behavioral tests were performed. Relative to their minimal expression in humans, G72 and G30 mRNAs were highly expressed in the transgenic mice, and had a more complex splicing pattern. The highest G72 transcript levels were found in testis, followed by cerebral cortex, with very low or undetectable levels in other tissues. No LG72 (the long putative isoform of G72) protein was detected in the transgenic mice. Whole-genome expression profiling identified 361 genes differentially expressed in transgenic mice compared with wild-type, including genes previously implicated in neurological and psychological disorders. Relative to wild-type mice, the transgenic mice exhibited fewer stereotypic movements in the open field test, higher baseline startle responses in the course of the prepulse inhibition test, and lower hedonic responses in the sucrose preference test. The transcriptome profile changes and multiple mouse behavioral effects suggest that the G72 gene may play a role in modulating behaviors relevant to psychiatric disorders.

Genetic tests of biologic systems in affective disorders.

To liberate candidate gene analyses from criticisms of inexhaustiveness of examination of specific candidate genes, or incompleteness in the choice of candidate genes to study for specific neurobiological pathways, study of sizeable sets of genes pertinent to each putative pathophysiological pathway is required. For many years, genes have been tested in a 'one by one' manner for association with major affective disorders, primarily bipolar illness. However, it is conceivable that not individual genes but abnormalities in several genes within a system or in several neuronal, neural, or hormonal systems are implicated in the functional hypotheses for etiology of affective disorders. Compilation of candidate genes for entire pathways is a challenge, but can reasonably be carried out for the major affective disorders as discussed here. We present here five groupings of genes implicated by neuropharmacological and other evidence, which suggest 252 candidate genes worth examining. Inexhaustiveness of gene interrogation would apply to many studies in which only one polymorphism per gene is analyzed. In contrast to whole-genome association studies, a study of a limited number of candidate genes can readily exploit information on genomic sequence variations obtained from databases and/or resequencing, and has an advantage of not having the complication of an extremely stringent statistical criterion for association.

Family-based association study of schizophrenia with 444 markers and analysis of a new susceptibility locus mapped to 11q13.3.

Family-based linkage disequilibrium (LD) mapping has been suggested as a powerful and practical alternative to linkage analysis. We have performed a genome-wide LD survey of susceptibility loci for schizophrenia in a Japanese population. We first typed 119 schizophrenic pedigrees (357 individuals) using 444 microsatellite markers, and analyzed the data using the pedigree disequilibrium test. This analysis revealed 14 markers demonstrating significant transmission distortion. To corroborate these findings, the statistical methods were changed to the extended transmission disequilibrium test (ETDT), using 80 independent complete trios (schizophrenic proband and both parents), with 68 derived from initial pedigrees and 12 newly recruited trios. ETDT supported two markers for continued association, D11S987 on 11q13.3 (P = 0.00009) and D16S423 on 16p13.3 (P = 0.002). We scrutinized the most significant genomic locus on 11q11-13 by adding 26 new markers for analysis. Results of three-marker haplotype analysis in the region showed evidence of association with schizophrenia (most significant haplotype P = 0.0005, global P = 0.022). Although the present study may have missed other potential genomic intervals because of the sparse mapping density, we hope that it has identified promising anchor points for further studies to identify risk-conferring genes for schizophrenia in the Japanese population. In addition, we provide useful information on genomic LD structures in Japanese populations, which can be used for LD mapping of complex diseases.

Association between serotonin 4 receptor gene polymorphisms and bipolar disorder in Japanese case-control samples and the NIMH Genetics Initiative Bipolar Pedigrees.

Possible irregularities in serotonergic neurotransmission have been suggested as causes of a variety of neuropsychiatric diseases. We performed mutation and association analyses of the HTR4 gene, on 5q32, encoding the serotonin 4 receptor in mood disorders and schizophrenia. Mutation analysis was performed on the HTR4 exons and exon/intron boundaries in 48 Japanese patients with mood disorders and 48 patients with schizophrenia. Eight polymorphisms and four rare variants were identified. Of these, four polymorphisms at or in close proximity to exon d, g.83097C/T (HTR4-SVR (splice variant region) SNP1), g.83159G/A (HTR4-SVRSNP2), g.83164 (T)9-10 (HTR4-SVRSNP3), and g.83198A/G (HTR4-SVRSNP4), showed significant association with bipolar disorder with odds ratios of 1.5 to 2. These polymorphisms were in linkage disequilibrium, and only three common haplotypes were observed. One of the haplotypes showed significant association with bipolar disorder (P = 0.002). The genotypic and haplotypic associations with bipolar disorder were confirmed by transmission disequilibrium test in the NIMH Genetics Initiative Bipolar Pedigrees with ratios of transmitted to not transmitted alleles of 1.5 to 2.0 (P = 0.01). The same haplotype that showed association with bipolar disorder was suggested to be associated with schizophrenia in the case-control analysis (P = 0.003) but was not confirmed when Japanese schizophrenia families were tested. The polymorphisms associated with mood disorder were located within the region that encodes the divergent C-terminal tails of the 5-HT(4) receptor. These findings suggest that genomic variations in the HTR4 gene may confer susceptibility to mood disorder.

Karyotype analysis of 161 unrelated schizophrenics: no increased rates of X chromosome mosaicism or inv(9), using ethnically matched and age-stratified controls.

Chromosomal aberrations have long been studied in an effort to identify susceptibility genes in schizophrenia. The two most frequently detected abnormalities are X chromosome mosaicism in female patients and pericentric inversions of chromosome 9 [inv(9)]. Chromosome X aneuploidies are known to be age dependent but differences due to ethnicity remain undetermined. In the case of inv(9), its prevalence in the general population varies with ethnicity. To evaluate the importance of these karyotypic changes in schizophrenia, cytogenetic analysis was performed on 161 unrelated schizophrenics of Japanese origin. We observed an increase in the incidence of X chromosome mosaicism in female schizophrenics with age. However, when compared with age matched female controls (92 individuals), no significant differences between patient and control samples were detected. Moreover, this study showed that there is no significant difference in the incidence of X chromosome loss between Japanese and Caucasian populations. The four cases with inv(9) (2.5%) detected in this study, did not differ significantly from the reported incidence of between 1.7 and 2.1% seen in the general Japanese population. We also observed a small number of additional karyotypic changes, none of which were recurrent. This is the first report to examine the comparative rates of X mosaicism in female schizophrenics and age matched controls.

Association studies of the cholecystokinin B receptor and A2a adenosine receptor genes in panic disorder.

Several lines of evidence implicate the cholecystokinin B receptor (CCKBR) and the A2a adenosine receptor (A2aAR) in the etiology of panic disorder. To determine the roles each of these receptors may play in panic disorder, we have performed a mutation screen on the CCKBR gene using single strand conformation polymorphism (SSCP) analysis and sequencing. We identified two novel but rare substitutions in the same allele, [3263G>C; 3264A>G], located in the 3'-untranslated region of the CCKBR gene. We then analyzed 91 unrelated patients and 100 matched controls for the four confirmed polymorphic sites in the CCKBR gene and the 1083C>T polymorphism in the A2aAR gene. No evidence of association between the described variants and panic disorder was found. Our data therefore suggests that the CCKBR and A2aAR genes do not play major roles in the development of this disease.

Identification of a compound short tandem repeat stretch in the 5'-upstream region of the cholecystokinin gene, and its association with panic disorder but not with schizophrenia.

The cholecystokinin gene (CCK) is thought to play a role in the pathogenesis of both panic disorder and schizophrenia. In this study, we have extended the 5'-upstream sequence of the CCK gene, and identified a compound short tandem repeat (STR), located approximately -2.2 to -1.8 kb from the cap site. This STR was found to be polymorphic with ten different allele lengths. Case-control studies using 73 panic patients, 305 schizophrenics and 252 controls showed a significant allelic association with panic disorder (P = 0.025), but not with schizophrenia. Dividing the STR alleles into three classes according to length, Long (L), Medium (M) and Short (S), produced strong genotypic (MM) (nominal P = 0.0014) and allelic (M) (nominal P = 0.0079) associations with panic disorder. screening the newly extended promoter region detected not only the previously identified -36c>t and -188a>g single nucleotide polymorphisms (SNPs) but a new rare snp, -345g>C. Neither of the former two SNPs showed significant association with either panic disorder or schizophrenia. Haplotypic distributions of the STR and SNPs -188 and -36 were significantly different between panic samples and controls (P = 0.0003). These findings suggest that the novel STR or a nearby variant may confer susceptibility to the development of panic disorder.

Evidence for association of the myo-inositol monophosphatase 2 (IMPA2) gene with schizophrenia in Japanese samples.

In our search for candidate genes for affective disorder on the short arm of chromosome 18, we cloned IMPA2, a previously unreported myo-inositol monophosphatase gene, that maps to 18p11.2. We determined its genomic structure and detected three new single nucleotide polymorphisms (SNPs). In the present study, we screened the gene further to search for additional polymorphisms in Japanese samples and identified seven other SNPs, including a novel missense mutation. These polymorphisms clustered into three regions of the gene. Three relatively informative SNPs, 58G>A, IVS1--15G>A and 800C>T from clusters 1, 2 and 3, respectively, were selected for association tests using a case-control design. The Japanese cohort included 302 schizophrenics, 205 patients with affective disorder and 308 controls. Genotyping was done either by melting curve analysis on the LightCycler or by sequencing. All three SNPs showed significant genotypic association (nominal P = 0.031--0.0001) with schizophrenia, but not with affective disorder. These findings increase the relevance of 18p11.2 to schizophrenia susceptibility because GNAL, which has been shown previously to be implicated in schizophrenia in an independent study, is in close physical proximity to IMPA2. Our findings suggest that IMPA2 or a gene nearby may contribute to the overall genetic risk for schizophrenia among Japanese.

Association studies of the CT repeat polymorphism in the 5' upstream region of the cholecystokinin B receptor gene with panic disorder and schizophrenia in Japanese subjects.

The tetrapeptide of cholecystokinin (CCK), CCK-4, is known to induce panic attacks in human subjects, while CCK-8 is reported to have a therapeutic effect on schizophrenia symptoms. Recently, we have identified a novel microsatellite polymorphism in the 5' upstream region of the CCK gene and shown a significant association between this polymorphism and panic disorder. In this study, we have investigated the CCK-B receptor (CCKBR) gene, which is the main constituent of the CCK receptor in the CNS. Recently, a dinucleotide repeat, (CT)(n), in the 5' regulatory region of the CCKBR gene was reported to be associated with panic disorder in Canadian samples. To evaluate an association of the CT repeat with panic disorder and schizophrenia, we genotyped 71 subjects with panic disorder, 154 schizophrenics and 199 controls. However, no evidence of allelic association was found between the polymorphic repeat of the CCKBR gene and either panic disorder or schizophrenia (P = 0.186 and 0.987, respectively). Together with the negative reports on association analyses using other polymorphisms of the CCKBR gene and Japanese samples, the present results exclude a major genetic contribution of the CCKBR gene to susceptibilities to panic disorder and schizophrenia in Japanese cohorts.

Association study on the DUSP6 gene, an affective disorder candidate gene on 12q23, performed by using fluorescence resonance energy transfer-based melting curve analysis on the LightCycler.

We introduced a new genotyping method, fluorescence resonance energy transfer-based melting curve analysis on the LightCycler, for the analysis of the gene, DUSP6 (dual specificity MAP kinase phosphatase 6), in affective disorder patients. The DUSP6 gene is located on chromosome 12q22-23, which overlaps one of the reported bipolar disorder susceptibility loci. Because of its role in intracellular signalling pathways, the gene may be involved in the pathogenesis of affective disorders not only on the basis of its position but also of its function. We performed association analysis using a T>G polymorphism that gives rise to a missense mutation (Leu114Val). No evidence for a significant disease-causing effect was found in Japanese unipolars (n = 132) and bipolars (n = 122), when compared with controls (n = 299). More importantly, this study demonstrates that melting curve analysis on the LightCycler is an accurate, rapid and robust method for discriminating genotypes from biallelic markers. This strategy has the potential for use in high throughput scanning for and genotyping of single nucleotide polymorphisms (SNPs).

Association study on the DUSP6 gene, an affective disorder candidate gene on 12q23, performed by using fluorescence resonance energy transfer-based melting curve analysis on the LightCycler.

We introduced a new genotyping method, fluorescence resonance energy transfer-based melting curve analysis on the LightCycler, for the analysis of the gene, DUSP6 (dual specificity MAP kinase phosphatase 6), in affective disorder patients. The DUSP6 gene is located on chromosome 12q22-23, which overlaps one of the reported bipolar disorder susceptibility loci. Because of its role in intracellular signalling pathways, the gene may be involved in the pathogenesis of affective disorders not only on the basis of its position but also of its function. We performed association analysis using a T>G polymorphism that gives rise to a missense mutation (Leu114Val). No evidence for a significant disease-causing effect was found in Japanese unipolars (n = 132) and bipolars (n = 122), when compared with controls (n = 299). More importantly, this study demonstrates that melting curve analysis on the LightCycler is an accurate, rapid and robust method for discriminating genotypes from biallelic markers. This strategy has the potential for use in high throughput scanning for and genotyping of single nucleotide polymorphisms (SNPs). Molecular Psychiatry (2000) 5, 489-494.

Structure determination and evolution of the chicken cDNA and gene encoding prepropancreatic polypeptide.

We have previously demonstrated that the C-terminal regions of the rat and human pancreatic polypeptide (PPP) precursors exhibit a high degree of divergence, whereas the N-terminal regions are highly conserved. This blend of structural conservation and divergence in the precursors appears to be caused by splice junction sliding and translational frameshift in the 3'-region of the PPP gene [Yonekura et al., J. Biol. Chem. 263 (1988) 2990-2997]. In the present study, we determined the nucleotide (nt) sequences of the chicken PPP (cPPP) cDNA and gene, and compared them with those of the mammals. In cPPP, the C-terminal region of the precursor is quite heterologous with respect to the rat (rPPP) and human (hPPP) precursors, and this heterogeneity is accentuated by the large deletion in exon 3 of cPPP. Furthermore, mutational accumulation during evolution caused the structural organization of the 3'-region of cPPP to change; cPPP is terminated in exon 3, whereas rPPP and hPPP are terminated in exon 4. Thus, our previous observation regarding the possibility of 'mosaic evolution' [Yamamoto et al., J. Biol. Chem. 261 (1986) 6156-6159] of PPP has been extended and confirmed by this study. Available evidence suggests that 'mosaic evolution' is a phenomenon unique to PPP, and not to the genes encoding the other members of the PPP family, neuropeptide-Y and peptide-YY.

Sporulation promoting factor in vegetative cells of Bacillus subtilis.

A simple experimental system for detection of sporulation promoting factors was presented. This system showed that there was a sporulation promoting factor in the vegetative cells of Bacillus subtilis cultivated on nutrient agar for 9 hr (at stage T0). The factor was partially purified from the sonicate of vegetative cells by ethanol fractionation, gel filtration, chromatography and preparative gel electrophoresis, and it was identified as manganese-containing protein.